Nickel-chromium alloys are known for their capability to afford various degrees of resistance to a myriad of both low temperature and high temperature corrosion environments. For this reason, these alloys are employed in a wide range of industrial and aerospace applications. Of particular utility is the use of nickel-chromium alloys in the thermal processing, chemical and petrochemical applications where high temperatures are essential for technical reasons and economy of operation. Such examples include furnace rollers in annealing furnaces and ceramic kilns, radiant tubes in heating furnaces, conveyor belts in sintering furnaces, muffles and retorts in furnaces and chemical process equipment, tubes for oxidizing titanium compounds to titanium dioxide paint pigment, thermocouple protection tubes and hardware for glass manufacture and glass verification of nuclear wastes.
By reason of their strength and corrosion resistance in such environments, alloys such as INCONEL.RTM. alloys 601, 617 and 690 (INCONEL is a trademark of Inco Alloys International, Inc.) and alloy 602CA are typically used in applications subject to high temperature oxidation. However, the trend towards increasing temperatures, more aggressive environments and the need for longer service life has stretched these alloys beyond their capabilities.
It is an object of this invention to provide an alloy having an improved combination of strength and general corrosion resistance for longer service lives than of existing commercial alloys.
It is a further object of this invention to provide an alloy with excellent carburization and oxidation resistance at elevated temperatures.
It is a further object of this invention to provide an alloy with excellent carburization and oxidation resistance under isothermal and cyclic conditions.